Portable boresight board



June24, 1969 J. H. ARNOLD 1 PORTABLE BORESIGHT BOARD Filed June 17. 1966 mm 6. \N MQ. S

United States Patent O U.S. Cl. 33-74 1 Claim ABSTRACT OF THE DISCLOSURE A portable boresight board for light and medium calibre weapons including a vertically adjustable center panel mounted on a movable base member, and a pair of hinged arms located on either side of the center panel having slidably mounted panels thereon.

The invention described herein may be manufactured and used by or for the United States Government for governmental purposes Without payment to me or any royalty thereon.

This invention relates generally to the practice of boresighting light and medium calibre weapons and more particularly to a means for boresighting a plurality of such weapons in elevation and azimuth simultaneously.

With the high performance aircraft presently in use, it is more important than ever lbefore that the ordnance, in the form of guns and rockets be in complete harmonization with their optical gun sights.

With the portable boresight board of this invention it is possible to accurately and rapidly provide harmonization between the optical sight and the weapons controlled thereby.

Ordinarily optical sights tend to be unstable, i.e., they will only remain harmonized with the guns for a short time, in fact, some sights require realignment after each mission.

Before my invention it was necessary to tow the aircraft to a range where the guns could be tired in, adjusted and made compatible with the sight. This, however, is not always possible since not all airelds have tiring ranges and in forward areas there is usually insuilicient turnaround time to check gun alignment.

It is therefore an object of this invention to provide a new means for harmonizing aircraft ordnance and gun sights.

It is a further object of this invention to provide a new and improved boresight board.

It is another object of this invention to provide a new and improved boresight board which is light weight and portable.

It is still another object of this invention to provide a new and improved boresight board which will harmonize a plurality of guns or rockets and the optical sight simultaneously.

It is still a further object of this invention to provide a new and improved portable boresight board which is readily adjustable in azimuth and elevation and can harmonize any aircraft gun or rocket system with its optical sight.

These and other advantages, features and objects of the invention will become more apparent from the following description taken in connection with the illustrative embodiment in the accompanying drawings, wherein:

FIGURE 1 is a front elevation view of the `boresight board of this invention;

FIGURE 2 is a cross section view of the adjustable gun panel embodied in this invention;

FIGURE 3 is a side elevation view partly in section of the clamping means securing the adjustable gun panel to the support member.

3,451,138 Patented June 24, 1969 ice Referring now to the drawings, the portable 'boresight board generally consists of a base trailer 10 allowing movement inv any direction on the ground, an adjustable center panel 12 which allows for corrections in elevation and two arms 14 and 16 which are adjustable in elevation and azimuth. The gun panels 18 and 20 are located on the arms depending upon the aircraft and ordnance concerned. The markings 22 on the sight panel line up with the cross hairs of the gun sight. The markings may be placed on thejsight panel for a particular aircraft or there may be a plurality of marking on the panel for all aircraft likely Ato be serviced.

The base 41,0 is made up of a triangular shaped frame shown generally at 24. The base members may be tubular or angular depending on choice, the only requirement being that they are suiciently rigid to sustain the weight of the panel 12 and arms 14 and 16. An upright member 26 having a T-shaped cross-section extends vertically from the base and is supported by angle shaped members 28 and 30. Castors 32 are mounted on the base for portability. The castors have a locking means (not shown) and provide la vertical adjustment for leveling the base through the adjusting nuts 34. Once in position the adjusting nuts are secured by the lock nuts. 36.

The panel 12 is vertically adjustable along the member 26 and guided by guide members 38. The panel is secured by the locking member generally shown at 40 in FIGURE 3, which is located behind the panel and at its base. A level 42 is located at the base of the panel in the front, on a leveling block 43 mounted in turn on the angular support 44. The angular support 44 forms the bottom of the panel and the mounting means for the arms 14 and 16. To facilitate the portability of the boresight board the arms 14 and 16 are hingedly mounted to the angular support 44 at pivot points 46 and 48. The arms may be raised and locked in the position shown at 14' by a suitable means at 52. The arms have a matching means for the means at 50.

Referring now to FIGURE 2 the gun panel 20 has riveted (54) thereto a bracing member 56 which has an angular bend extending transversely to the longitudinal axis of the brace, away from the panel. This portion of the brace acts as a bearing surface and rides on the arm (14 or 16). Extending outwardly and below the portion of the brace 56 is another brace 57 which has a locking member 58 consisting of a U-shaped bearing surface which rides on the arm (14 or 16) and a locking bolt 60 extending therethrough. In operation the locking bolt is loosened and the panel slides along the arm to the desired location, then the lock bolt is tightened and the panel is held secure.

In FIGURE 3 is shown the means provided to vertically adjust the sight panel 12. A bolt 62 has a knob 64 mounted at one end. The bolt extends through a channel member 66 which slides on the extending web of the support member 26. The bolt then continues through the angle member 44 at the base of the sight panel 12 and into the lock nut 68; a washer 70 is placed 'between the lock nut and the sight panel. If desired, the lock nut may be secured as by welding to the panel to eliminate the need of using a tool to hold it while loosening or tightening the bolt.

In operation the knob 64 is loosened which in turn releases the channel member gripping the web of the support. The panel is then raised or lowered to the desired position and the knob is tightened holding the panel in place.

If the panel is large it would be desirable to replace one of the guide members with a second or third locking means to insure that the panel will not move.

I Claim:

1. A portable boresight board comprising: a base having a plurality of wheels and means for the leveling there- 3 4 of; a vertical support member having a T-shaped cross- References Cited section mounted on the base; a horizontal support means UNITED STATES PATENTS adjustably mounted on the vertical support means includ- 922 833 5/17909 Young ing a level indicator means and a means for locking the 21491362 3/1939 MacMillan horizontal support means in position along the vertical 5 2,516,435 7 /1950 Trimbach et al- 33 462 support means; a target panel mounted on said horizontal FOREIGN PATENTS support and held against the vertical support by guide means; a pair of arms mounted in hinged relation to the 362,614 1/1906 Francehorizontal support on either side of the vertical support 364986 12/1922 Germany' having target panels slidably mounted thereon. 10 ROBERT B. HULL, Primary Examiner. 

